MHT CET · Physics · Thermal Properties of Matter
The emissive power of sphere of area \(0.04 \mathrm{~m}^2\) is \(0.7 \mathrm{kcal} \mathrm{s}^{-1} \mathrm{~m}^{-2}\). The amount of heat radiated in 20 second is
- A \(2.8 \mathrm{kcal} \mathrm{s}^{-1} \mathrm{~m}^{-2}\)
- B \(0.28 \mathrm{kcal} \mathrm{s}^{-1} \mathrm{~m}^{-2}\)
- C \(5.6 \mathrm{kcal} \mathrm{s}^{-1} \mathrm{~m}^{-2}\)
- D \(0.56 \mathrm{kcal} \mathrm{s}^{-1} \mathrm{~m}^{-2}\)
Answer & Solution
Correct Answer
(D) \(0.56 \mathrm{kcal} \mathrm{s}^{-1} \mathrm{~m}^{-2}\)
Step-by-step Solution
Detailed explanation
Emissive power \(E=\frac{Q}{A t}\)
\(
\therefore Q=E A t=0.7 \times 0.04 \times 20=0.56 \mathrm{kcal} \mathrm{s}^{-1} \mathrm{~m}^{-2}
\)
\(
\therefore Q=E A t=0.7 \times 0.04 \times 20=0.56 \mathrm{kcal} \mathrm{s}^{-1} \mathrm{~m}^{-2}
\)
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